Clean up some ash constants.

ash/system/tray/tray_constants.h

Index: ash/system/tray/tray_constants.h
diff --git a/ash/system/tray/tray_constants.h b/ash/system/tray/tray_constants.h
index 16ae1a2a0d43feddf1476cc1a54c9c5a06189ca0..6443155faaf5f0c641743af9e485a85a8ac3c6da 100644
--- a/ash/system/tray/tray_constants.h
+++ b/ash/system/tray/tray_constants.h
@@ -22,6 +22,10 @@ extern const int kBubblePaddingHorizontalSide;
 extern const int kBubblePaddingVerticalBottom;
 extern const int kBubblePaddingVerticalSide;
 
+// The size delta between the default font and the font size found in tray
+// items like labels and buttons.
+extern const int kTrayTextFontSizeIncrease;
+
 extern const int kTrayBubbleAnchorTopInsetBottomAnchor;
 
 extern const int kTrayImageItemHorizontalPaddingVerticalAlignment;